1. Field of the Invention
The present invention relates to an image processing apparatus for processing an output image on the basis of the feature of an image extracted from an input image.
2. Related Background Art
In recent years, remarkable advances have been made in color printing systems such as a color printing apparatus for digitally processing color image data, and outputting the processed color image data to a color printer to obtain a color image, a digital color copying machine for color-separating and electrically reading a color original image, and printing obtained color image data on a paper sheet, and the like.
Along with the spread of these systems, a demand for a higher printing quality of color images is becoming stronger. In particular, it is required to print black characters and black thin lines to be sharp black ones. More specifically, when a black original image is color-separated, yellow, magenta, cyan, and black signals are generated as those for reproducing black. When image data is directly printed on the basis of the obtained signals, since a black image is reproduced by superposing four colors, color smearing occurs in a black thin line due to slight misregistrations among colors, and an original black image cannot be seen in black or is blurred, thus considerably deteriorating printing quality.
In order to solve this problem, the following method is proposed. That is, the areas of black characters, color characters, and the like are detected or an original image is divided into a halftone image area, a screen image area, and the like by extracting the features such as color information of black or other colors in an image signal, and the spatial frequencies of thin lines, screens, and the like, and processing is executed in correspondence with the detected or divided areas. If the detected area is a black character area, the area is printed using black alone.
Furthermore, the present applicant proposed, in Japanese Laid-Open Patent Application No. 7-203198, an improved method which can obtain clearly different processing results at the boundary lines of black character processing by discriminating the thickness of each character, and executing black character processing in correspondence with the discriminated thickness.
Japanese Laid-Open Patent Application No. 7-203198 also proposed a method of setting the black character processing area and the degree of black character processing in correspondence with a user""s favor.
However, the conventional method does not take into account the above-mentioned black character processing for image data supplied from a host computer. For this reason, black character processing with noise-free, sharp edge, and good gray balance features, and the like cannot be performed for computer graphics images.
The present invention has been made in consideration of the above situation, and has as its object to execute feature detection processing suitable for images input from a plurality of input means.
In order to achieve the above object, according to the present invention, there is disclosed an image processing apparatus comprising:
first input means for inputting a first set of plural color component signals;
second input means for inputting a second set of plural color component signals;
judging means for judging a line image portion having a specific color of an image represented by the first or second set of plural color component signals; and
setting means for setting a judging standard for the judging means.
It is another object of the present invention to provide an image processing method and apparatus, which can realize black character processing that can set coefficients suitable for image processing for image data supplied from a host computer (external apparatus) without requiring any instruction for setting image processing coefficients to be supplied from the host computer when black character processing is performed for an image supplied from the host computer.
It is still another object of the present invention to provide an image processing method and apparatus, which can realize black character processing that can change the degree of black character processing in accordance with an instruction from a host computer or a console unit of the main body.
It is still another object of the present invention to provide an image processing method and apparatus, which can perform optimal image processing when an image supplied from a host computer and an original image read from a scanner are mixed.
It is still another object of the present invention to provide a multi-functional interface between a host computer and an image forming apparatus.
It is still another object of the present invention to satisfactorily control UCR processing for an image supplied from a host computer.